Many contemporary methods of molecular biology, including nucleic acid hybridization analysis and protein binding analysis, utilize “biochips” or arrays of probe biomolecules (“probes”) to bind and detect target biological species (“targets”) in complex sample systems. Most commonly in these methods, a sample is simply placed onto the surface of the array and targets contained in the sample passively diffuse toward and bind with the probes immobilized on the support. A fusion of biotechnology, nanotechnology, and micro electro mechanical system (MEMS) technology has led to new technology. For example, biochips and DNA chips have been developed, and are being commercialized in an array formation.
Recently, the concept of Lab-on-a-Chip (LOC) has been introduced to integrate all processes performed in labs into a biochip. The processes include pre-treatment, derivatization, separation, detection, and analysis of various samples such as biological samples, e.g., blood, urine, cells, or saliva, natural substances, chemicals, food, or medicines. DNA-LOCs and protein-LOCs, into which all these lab processes are integrated, are being developed.
Moreover, a carbon nanotube has been used as a major component of a miniaturized cathode-ray tube and applied in various fields. For example, carbon-based nanotubes may be used to fabricate nano-sized microscopy probes. Also, stable iodine-doped carbon nanotubes have been fabricated by doping carbon nanotubes with iodine and fabricated nano-sized metallic nanoscale fibers.
In addition, electrochemiluminescent ruthenium complexes using functional group biomolecule-modified nanotubes have been fabricated. Also, carbon nanotubes have been used in developing high-density and large-capacity biosensors.
A conventional biochip may be fabricated by synthesizing a single strand of DNA on a desired region of a substrate or by spotting a pre-manufactured single or double strand of DNA on a predetermined region of a substrate. However, there is a high possibility that the biomolecular probes to be attached will be aligned randomly on the substrate. Furthermore, the density of the biomolecular probes in a region of the substrate where the biomolecular probes hybridize may be low. Therefore, it is difficult to analyze target DNA precisely.